This disclosure relates in general to chemical, biological, and explosive detection and, but not by way of limitation, to detection by determining exposure of a media.
Analysis in most current detection systems employs ion mobility spectroscopy as the mechanism for detecting items of interest. The detection capture and analysis devices may be installed in the infrastructure being protected such as at the portals for entry or exit, positioned to capture from the persons involved through contact (e.g., touch or swipe) or may be handheld and employed by those protecting the infrastructure. Such devices are common in airports today. The devices typically are slow in the capture and analysis process, frequently require operator participation and require regular cleaning, potentially after each use. In addition, the analysis results are frequently ambiguous, resulting in high false alarm rates. Rates of false alarms for ion mobility spectrometry is approximately 2%.
Detection of trace particles or emanations from compounds which may represent a threat to the public is based on the capture and analysis of the material. Capture may be accomplished through contact (e.g., wipe a surface or contact with a capture surface) or through capture from the atmosphere (e.g., forced air flow such as a “puffer” to dislodge particles from surfaces or through vapor sampling from the atmosphere).
An emerging class of detection devices relies on the capture of the threat indicating material causing a change in the composition of the material of the device which captures it. The change is then observable or causes a detectable change in the reflective photo luminescence. Optical scanners may be employed to detect the change in luminescence when the capture material is presented. In cases where the change in the capture material is visible, the holder may dispose of the device before the capture event is recorded or associated with the person.